Opponents consider the Dream Act a form of amnesty and have accused Reid and other Democrats of using it to appeal to Hispanic voters, an important constituency, as the midterm elections approach. Supporters, who include retired Gen. Colin L. Powell and other military officials, have argued that the measure is long overdue, humane and practical.

The Dream Act would open the door to citizenship for undocumented immigrants younger than 36 who arrived in the United States as children, have lived here for five years or more, and are contributing to the country by attending college or serving in the military.

Although about 2.1 million of the approximately 11 million undocumented immigrants in the country could be eligible for legalization under such criteria, the Migration Policy Institute has estimated that only about 825,000 people would be able to take advantage of the provision.

The prospects for the legislation to pass are considered slim, particularly given the public's embrace of tough immigration laws in Arizona and other states. Several versions of the Dream Act have been debated in Congress over the past decade, but none of the measures has succeeded.

Nevertheless, Powell argued for its passage Sunday on NBC's "Meet the Press."

"We have millions and millions of illegal immigrants in our country, undocumented individuals who are working, who are doing things we need done in this country," he said. While acknowledging the need for tighter border controls to reduce illegal immigration, the former secretary of state told host David Gregory that immigrants "are all over my house doing things whenever I call for repairs, and I am sure you have seen them at your house. We have got to find a way to bring these people out of the darkness and give them some kind of status."

The maneuvering in the Senate comes as Reid is locked in a tight reelection battle against Republican Sharron Angle, a favorite of the "tea party" movement.

Polls show that Reid is in a dead heat with Angle or narrowly ahead. Hispanic voters, who constitute as much as a quarter of voters in the state, are expected to strongly back passage of the Dream Act. For the moment, both the Reid and Angle campaigns are betting the issue will help them.

In a campaign ad released last week, Angle suggested that the Senate majority leader is the "best friend" that illegal immigrants could have.

"Instead of addressing the unemployment issue, Harry Reid will spend this week in Washington D.C. trying to push a form of amnesty through the Senate," Angle said in a statement. "Sadly, the Dream Act is another attempt to incentivize illegal aliens to cross our borders to gain citizenship."